Lin Tsai-Yu, Wong Lee-Chin, Hou Pei-Shan, Wu Chia-Kai, Cheng Haw-Yuan, Zhao Hong-Jun, Tung Chien-Yi, Lee Mei-Hsuan, Lee Wang-Tso, Tsai Jin-Wu
Institute of Brain Science, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.
Laboratory of Molecular Regulation of Neurogenesis, GIGA-Stem Cells and GIGA-Neurosciences, Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), University of Liège, Liège, Belgium.
Mol Psychiatry. 2025 Jun 16. doi: 10.1038/s41380-025-03077-y.
FOXG1 (Forkhead Box G1) is a critical transcription factor for brain development, regulating progenitor cell proliferation, neuronal migration, and cortical circuit assembly. Pathogenic FOXG1 variants lead to FOXG1 syndrome, a neurodevelopmental disorder characterized by severe brain anomalies and cognitive impairments. Despite efforts to correlate genetic variants with clinical outcomes, the precise relationship remains elusive. Here, we analyzed clinical severity and brain anomalies in 14 individuals with FOXG1 variants, investigating how these variants impact FOXG1's properties and functions. We uncovered a strong correlation between the severity of brain anomalies in affected individuals and functional alterations of these variants. Variants with very low protein expression were associated with moderate-to-severe brain anomalies. A luciferase reporter assay was used to assess the ability of FOXG1 variants to repress COUP-TFI (NR2F1) expression-a function of FOXG1 validated through single-cell RNA-sequencing (scRNA-seq). Variants losing COUP-TFI repression ability by binding to COUP-TFI's enhancer region consistently caused moderate-to-severe brain anomalies. Furthermore, in utero electroporation (IUE) in embryonic mouse brains was employed to study their impact on neuronal migration and differentiation. Electroporation of wild-type Foxg1 delayed neuronal migration and altered their cell fate. Remarkably, variants associated with moderate-to-severe brain anomalies impaired these functions, while those with mild brain anomalies caused partial impairment. Thus, by combining protein expression, COUP-TFI repression, and neuronal migration assays, we developed a patient stratification paradigm for predicting the severity of FOXG1 syndrome. This workflow successfully differentiated 92.3% of cases, facilitating early diagnosis and guiding future therapeutic interventions.
FOXG1（叉头框G1）是大脑发育的关键转录因子，调控祖细胞增殖、神经元迁移和皮质回路组装。致病性FOXG1变异导致FOXG1综合征，这是一种神经发育障碍，其特征为严重的脑异常和认知障碍。尽管人们努力将基因变异与临床结果相关联，但确切关系仍不明确。在此，我们分析了14名携带FOXG1变异个体的临床严重程度和脑异常情况，研究这些变异如何影响FOXG1的特性和功能。我们发现受影响个体的脑异常严重程度与这些变异的功能改变之间存在强烈关联。蛋白质表达极低的变异与中度至重度脑异常相关。采用荧光素酶报告基因检测来评估FOXG1变异抑制COUP-TFI（NR2F1）表达的能力——通过单细胞RNA测序（scRNA-seq）验证的FOXG1的一项功能。通过与COUP-TFI的增强子区域结合而失去COUP-TFI抑制能力的变异始终导致中度至重度脑异常。此外，利用胚胎小鼠脑内电穿孔（IUE）来研究它们对神经元迁移和分化的影响。野生型Foxg1的电穿孔延迟了神经元迁移并改变了它们的细胞命运。值得注意的是，与中度至重度脑异常相关的变异损害了这些功能，而那些脑异常较轻的变异则导致部分损害。因此，通过结合蛋白质表达、COUP-TFI抑制和神经元迁移检测，我们建立了一种用于预测FOXG1综合征严重程度的患者分层模式。该工作流程成功区分了92.3%的病例，有助于早期诊断并指导未来的治疗干预。
